Wireless communication and devices for communicating wirelessly are becoming increasingly popular. Different applications of wireless communication require different wireless communication interfaces, protocols, frequencies, specifications, and standards, so that different devices are required. For example, contactless payment systems allow a user to effect payment for some purchases by tapping or waving a card (or other payment instrument) near a contactless payment reader at a merchant point of sale. These systems provide an alternative to “swiping” a card through a point of sale terminal to read information from a magnetic strip on the card. In a contactless payment system, a microcontroller embedded in the card typically securely holds identifying or payment information, such as the number of an account from which payments are to be made, in a memory. In some systems, when the card is brought within range of the reader, an antenna in the card derives power from a radio signal emanating from the reader, and uses the power to operate an electronic chip on the card. A financial application residing in the microcontroller initiates a sequence of commands to exchange transactional data between the contactless card and the contactless reader. Once the information is verified, a purchase can be approved and finalized very quickly. Some contactless payment systems operate on a carrier frequency of 13.56 MHz.
Another example of a wireless communication application is the interconnection of electronic devices according to the Bluetooth communication standard promulgated by Bluetooth SIG, Inc. In a Bluetooth-enabled system, devices can exchange digital data with each other over distances of a few meters. Typical applications include transmitting audio information between a cellular telephone and an earpiece to enable hands-free operation of the cellular telephone. Bluetooth communications use a frequency-hopping system to transmit on frequencies between 2.40 and 2.4835 GHz. (The cellular telephone as used for its primary purpose of making telephone calls is yet another example of a wireless communication device, using frequencies and protocols different from both contactless payment systems and Bluetooth-enabled devices.)
Bluetooth communications are incompatible with contactless payment readers in several ways, including both frequency and protocol.